All marine vessels have a bottom paint or coating designed to discourage weeds, barnacles, and other aquatic organisms from attaching themselves to (and in the case of wooden boats, eating) the underwater portion of a vessel's hull. If the vessel stays in the water year round or during most or all of the boating season, application of bottom paint is pretty much the rule. Periodic bottom-paint application, cleaning, and renewal become a permanent part of the vessel's routine maintenance schedule.
There are numerous examples of sanding devices for abrading curved surfaces such as the sides and bottom of vessels in the prior art—U.S. Pat. No. 4,102,084 (Blomquist) and U.S. Pat. No. 7,022,044 (Böhler). However, these devices must be handheld. A great amount of manual strain and human exertion is required for sanding and surface preparation while manually pushing heavy random orbital sanders up against the sides and bottoms of the vessel. In addition, the operator is required to crouch, bend, and twist to maintain adequate force on the abrading device to sand or polish the surface, or build platforms and use extenders to access higher elevation work areas.
U.S. Pat. No. 6,991,529 (Annis et al.) describes a hand manipulated tool for sanding, but this apparatus still requires considerable manual exertion to make contact force with a curved surface.
U.S. Pat. No. 8,517,799 (Panergo et al.) uses a double ball joint connecting a random orbital sander to a robot for sanding and polishing airplanes in a factory floor environment. This is a similar application to vessel surface preparation, but the robot is designed for multiple replications of the same surface (assembly stalls for airplanes) where the factory floor environment and the object surface to be sanded and polished is predictable. It is noted that U.S. Pat. No. 6,352,227 (Hathaway) describes a similar segmented, ball joint support for tools, lamps, cameras and faucets.
The problem with all prior art is that automated, robotic sanders are designed for factory floor environments on multiple products where the pathway for the robot can be determined and replicated many times. The problem with maintenance of an aquatic vessel is that the size and shape of surface to be sanded and polished is unknown, the job is one-of-a-kind to the contractor performing the maintenance; and the workplace environment is variable. Owners of large vessels may be unwilling to bring their vessel to the apparatus (that is, a robotic sanding station), but insist that the maintenance be performed on their dock or on the water where the vessel is located.
Therefore, the object of this invention is to provide a semi-automated vessel surface sanding and polishing apparatus that can eliminate human exertion; reduce labor; and reduce the duration to perform surface sanding and polishing of the sides and bottoms of vessels subject to periodic bottom-paint application, cleaning, and renewal.